The present invention relates to determining the accumulated vibration stress fatigue of an electronic system, and more particularly to a calibrated micro-electro-mechanical structure (MEMS) which is monitored to determine the accumulated printed wiring board flexure due to mechanical vibration.
During its design life, electronic systems can be exposed to a wide variety of vibration and shock environments. In order to reduce testing time and cost, laboratory tests are typically conducted on electronics in a time-accelerated manner and results extrapolated to the intended application environment using various theoretical predictive mathematical models.
Electronic systems are complex structures with characteristics that may make accurate predictive analysis quite difficult. Further complicating predictive analysis is that the life-environment actually experienced by each particular electronic system is unique. Such individuality is particularly prevalent in the vibration-fatigue life of military and commercial avionic systems. Such predictive analysis, although effective, may not define the risk for all possible failures. Known in-service time, or known number of flights, missions, etc. may not accurately predict actual cumulative fatigue experienced by individual units. This may result in unanticipated failures or unnecessary anticipatory preventative maintenance and repair which may increase the associated life cycle costs. Accordingly, it is desirable to provide an in-situ monitoring system and method to determine if an electronic system is near the end of a vibration-fatigue life based on the life-environment actually experienced.